Field of the Invention
The present invention relates to an ophthalmologic apparatus for observing or photographing a fundus of a subject's eye, and a method for controlling the same.
Description of the Related Art
Conventionally, there is known an ophthalmologic apparatus for observing or photographing a fundus, which captures focusing index images split and projected at the fundus of a subject's eye, and detects a positional relationship among the focusing index images to perform autofocusing.
One of the plurality of focusing index images may be vignetted at the subject's eye due to a small pupil or a cataract of the subject's eye. To deal with this issue, Japanese Patent Application Laid-Open No. 2009-172154 discusses a method for performing autofocusing by using a difference between a visible focusing index image and a preset focusing reference position fixed to an image sensor when only one of two split and projected focusing index images can be captured.